They probably left a bypass valve open somewhere that is letting hot water come back through a cold water line. I can't imagine this would affect the whole building though--are all the units having this same problem?

: Terry:

: GREAT SITE!!!! Now a question...The apartment complex I moved into just put in a new water heater: yesterday.

: Now we get hot water from BOTH the cold and hot water faucets. They've trying to fix it all day. : It cooled off for a little while but now its hot from both. Originally they thought they had forgotten : to turn the cold water on. Now they don't seem to know what's going on. Could they have reversed the : cold and hot water hook ups? Management seems to be clueless. I vaguely recall something about: in an This Old House episode.